The invention relates to the field of micro-electronics and that of power electronics; it also relates to the power function controlled by MOS Smart Power logic. It relates to and is also applicable to interconnections with intersecting high voltage and low voltage zones in integrated power devices or to the interconnections of devices passing above a lightly doped, active zone.
In integrated circuits for power electronics, interconnections are a problem that is difficult to solve. One of the problems resides in making high voltage metal tracks that pass over a low voltage active zone.
In silicon, the high and low voltage zones are separated by a lightly doped buffer zone in which the potential gradually varies from the high to the low voltage: this buffer zone may also be insulating. A metal track which passes above this buffer zone strongly interferes with it. The voltage of this buffer zone can fall from 650 V to 200 V.
Means currently used to counter this problem are:
very thick oxide on the silicon and under the metal to cause maximum separation of the metal track from the buffer zone ; for example, a separation of about 8 xcexcm for a maintained voltage of 600 V, which is technologically difficult to create,
the so-called xe2x80x9cpackagingxe2x80x9d method which enables one to make connections using the package, the wires passing very far away from the buffer zone. This method is a non-integrated method.
The object of the invention is an interconnection device for at least two electronic elements, separated by at least one buffer zone, the interconnection comprising one or more interconnection tracks for the elements, the track being perforated at least in the parts of the track or tracks situated above or close to the buffer zones.
By electronic elements one understands any conductive or semi-conductive zone of an electronic circuit that can be interconnected. These zones may be, for example, zones of high or low voltage, connection contacts, etc. and the electronic circuits may be diodes, transistors etc.
Generally, the interconnection track or tracks (also called lines of interconnection) are separated from the one or more buffer zones by an insulating layer. Advantageously, this insulating layer is silicon oxide, notably for elements produced in silicon.
The creation of perforated tracks or interconnection lines, for example in the form of perforated metal layers, permits a clearly improved distribution of the potential, within the buffer zone. The maintained voltage of the buffer zone rises to about 500 V. The fact of using a perforated track or perforated interconnection lines enables field lines to leave the buffer zone through the holes made in the track or in the interconnection lines.
The track or the interconnection lines can be created in the form of a perforated metal layer, that is to say a metal layer with a large number of holes or slits. The holes can, for example, be in the form of a honeycomb.